Steam Quality (Dryness Fraction) Calculator mechanism

Model scope

The core quality formula is correct, but the instrument needs explicit validity checks, absolute-pressure handling, property-unit declarations, a defined interpolation scheme for both pressure and temperature inputs, and a precise definition of any additional mixture properties. The honest label should state the table source, table resolution, rounding, interpolation method, and an accuracy limit or error estimate; 'approximately saturation table resolution' is not a quantified accuracy claim.

• The formula x=(y-yf)/(yg-yf) is the standard saturated-mixture quality relation for specific enthalpy h, specific entropy s, or specific volume v, provided yf and yg are saturated-liquid and saturated-vapor values at the same saturation pressure or temperature.
• The specification does not define the interpolation variable or method. Interpolation must be explicitly defined separately for pressure-based and temperature-based lookup, and linear interpolation of rounded table values is only an approximation.
• The claimed output 'mixture properties' is underspecified. Quality alone does not define which additional properties are returned or the equations used to calculate them.
• The specification does not state whether h, s, and v are mass-specific quantities; the formula is invalid if mixed with molar or total properties.
• The formula applies only inside the two-phase saturation dome, including the limiting states x=0 and x=1. It is not valid for compressed liquid, superheated vapor, or supercritical states.

Units and conventions

• Temperature inputs are in degrees Celsius for the temperature-based vectors; saturation-table interpolation is performed in degrees Celsius.
• Pressure inputs are absolute pressure, not gauge pressure; the pressure-based vector uses 1.000 MPa absolute.
• Specific enthalpy h is in kJ/kg, and specific volume v is in m^3/kg. Specific entropy, if supported, must use one consistent mass-specific unit such as kJ/(kg K).
• Saturated-liquid and saturated-vapor reference values must use the same pressure or temperature and the same property units as the measured input.
• The tabulated values below are rounded standard steam-table values; calculations use the displayed rounded values exactly.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "temperature_C": 100,
    "property": "specific enthalpy",
    "h_kJ_per_kg": 419.04
  },
  "expected_outputs": {
    "quality_x": 0,
    "phase_state": "saturated liquid boundary",
    "saturation_pressure_kPa": 101.325,
    "mixture_specific_enthalpy_kJ_per_kg": 419.04
  },
  "reference_data": {
    "temperature_C": 100,
    "saturation_pressure_kPa": 101.325,
    "hf_kJ_per_kg": 419.04,
    "hg_kJ_per_kg": 2675.5,
    "source_convention": "IAPWS-IF97 standard steam-table values, rounded to the displayed precision; 100 C saturation pressure is the widely memorized standard value 101.325 kPa"
  },
  "working": "At 100 C, yf=hf=419.04 kJ/kg and yg=hg=2675.5 kJ/kg. x=(h-hf)/(hg-hf)=(419.04-419.04)/(2675.5-419.04)=0/2256.46=0.000000. Therefore x=0 and the state is saturated liquid. The saturation pressure is the table value 101.325 kPa."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The critical-point vector makes hg - hf exactly zero and the quality expression becomes 0/0. An implementation without an explicit critical-point and zero-denominator guard can produce NaN, an exception, or an invalid quality. The branch and unit vectors also expose required rejection and convention checks outside the two-phase dome.

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche7/tranche7-results.json
• BOUNDARY_HAZARD_CATALOG.json